The present invention relates to mammalian antiviral therapy. More particularly, it concerns the use of novel hematopoietic cells to reduce or eliminate human HIV infection.
Recent advances in human HIV anti-retroviral therapy have included the development of powerful combinations of anti-retrovirals including nucleoside analogue and non-nucleoside analogue reverse transcriptase inhibitors used simultaneously with protease inhibitors. Nevertheless, the problem of de novo and, especially, acquired drug resistance is significant. Acquired drug resistance is now understood to be statistically more likely with greater viral load.
Prior art has identified that certain individuals are seemingly immune from HIV infection. These individuals seem to lack a normal CKR-5 co-receptor on the lymphocyte surface that must be assessed along with the CDR receptor for viral attachment.
Additional prior art has demonstrated the ability to use placental blood as a substitute for cross-matched donor stem cells in marrow transplants, and from prior art, we know that autologous human stem cells can be harvested and induced to reproduce in vitro.
Human retroviral infection with one of the variants of the HIV virus has been impossible to cure in vivo. In fact, antiviral pharmaceuticals have had limited success in retarding the infection and prolonging life. Despite a variety of pharmaceutical approaches, unfortunately, the virus has been able to develop drug resistance in each host, making it seemingly impossible to eradicate the viral infection and to control secondary infections such as CMV, retinitis, pneumocystis, pneumonia, etc.
The present invention reduces the viral replication process by using modified, novel hematopoietic cells. The multidrug antiviral and chemotherapy course can be used to eradicate the retroviral infection. Optimal time of therapy is disclosed and analyzed herein.
The pattern of emergent drug resistance in HIV infection is the result of the very high viral titers in advanced HIV infectionxe2x80x94the acquired immunodeficiency syndrome (AIDS). Such high viral counts mean that drug resistance due to viral mutations is more likely. That is to say, the retroviarl RNA mutation rate is roughly equivalant to other RNA and DNA mutation rates. But, in advanced HIV infection (AIDS), in particular, the number of replicating virons is in the billions, making it more likely statistically that drug resistance will emerge. In the hostile environment of systemic antiviral chemotherapy, the mutant virons will be xe2x80x9cselected for.xe2x80x9d Thus, in the individual AIDS patient, the potential for drug resistance is very high.
This invention reduces the viral xe2x80x9cbattlegroundxe2x80x9d to the micro-environment of a single cell by first designing a host cell that is devoid of the infrastructure or function necessary for viral replication. This host cell has the surface receptors (CD4) in a normal or even increased density required for retroviral incorporating into the host cell. These modified lymphocytes are used to xe2x80x9csoak upxe2x80x9d virons into a sterile environment during a multidrug regimen. By reducing the opportunity for drug resistance mutations, the present invention can be used to eradicate or significantly suppress the infection. Secondly, the present invention purposely eliminates or reduces the normal stem cell population which ultimately produces the lymphocytes susceptible to viral replication. The present invention. Repopulates the bone marrow with stem cells that produce lymphocytes lacking the CKR-5 receptors.
It is an object of this invention to provide for modification of lymphocyte target cells to reduce sterile (xe2x80x9cdronexe2x80x9d) and/or hostile (xe2x80x9ccruisexe2x80x9d) host cells that reduce the viral load to below 200 copies per mm3 when infused to a concentration of 1,000 to 1,000,000 or more cells per mm3 and thereby mitigate the chances of emergent drug resistance during the course of antiviral treatment for retrovirus infection.
Another object of this invention is to provide a lymphocyte target cell of the type as just previously described wherein the cellular mechanisms required for viral replication are inactivated or deleted (xe2x80x9cdronexe2x80x9d lymphocyte).
Another object of this invention is to provide a lymphocyte target cell wherein its pretreatment with a multidrug array of antivirals creates a furthering of the ability of the virus to replicate (xe2x80x9ccruisexe2x80x9d lymphocytes), particularly after the cellular mechanisms have been treated to inactivate or delete viral replication.
Another object of this invention is to provide for an isolation of autologous lymphocytes through the use of leukophoresis techniques for the purpose of mitigating the chances of emergent drug resistant virus during the course of antiviral treatment for retrovirus infection.
Yet another object of this invention is to provide the method for harvesting of lymphocytes for their modification through the use of the process of this invention wherein the lymphocytes may be stored for future usage.
Another object of this invention is to provide for the periodic use of leukphoresis to remove spent modified lymphocytes and to replenish the count of modified lymphocytes generated in accordance with this invention.
Yet another object of this invention is to provide the method for timing of intervention of the principal method of this invention as previously described, preferably before a significant reduction in CD4 T-cell count.
Another object of the present invention is to reduce or eliminate lymphocytes susceptible to HIV replication by repopulating the marrow with modified stem cells which do not express the CKR-t receptor on their derivative lymphocytes.